A typical handheld measurement system consists of software and simple hardware attachments for a given PDA (personal digital assistant) such as the Palm. Sensors are attached to the hardware, turning the Palm handheld into a state-of-the-art, handheld test and measurement instrument. By using the PDA or Palm handheld as a measurement device there is an increase in the amount of time the Palm handheld is in use. This places an ever-increasing demand on the amount of time the handheld devices are able to provide functionality between rechargings or repowerings.
Currently the most effective way of conserving power, and thereby extending the amount of time a handheld measurement device may be used, is simply turning the device off. The problem with this is that it also reduces the effectiveness of the device's measurement capability when monitoring sensors when the user is away. In cases, as mentioned above, where the handheld measurement device has additional functionality this functionality cannot be used when the device is off. In addition, turning the device on requires an additional power draw, above the usual operational power consumption of the device, which serves to further reduce the power reserves of the device.
Consequently, a need exists for power management on handheld measurement devices that reduces the power consumption of the device while retaining at least some of the functionality of the device.